This may be considered the initializer of the protocol, because it is
called when the connection is completed. For clients, this is called once
the connection to the server has been established; for servers, this is
called after an accept() call stops blocking and a socket has been
received. If you need to send any greeting or initial message, do it
here.

Return True if the given lower-cased name is the name of a
connection control header (rather than an entity header).

According to RFC 2616, section 14.10, the tokens in the Connection
header are probably relevant here. However, I am not sure what the
practical consequences of either implementing or ignoring that are. So I
leave it unimplemented for the time being.